cubefs

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package sarama
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import (
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	"fmt"
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	"strings"
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	"github.com/rcrowley/go-metrics"
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)
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// Use exponentially decaying reservoir for sampling histograms with the same defaults as the Java library:
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// 1028 elements, which offers a 99.9% confidence level with a 5% margin of error assuming a normal distribution,
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// and an alpha factor of 0.015, which heavily biases the reservoir to the past 5 minutes of measurements.
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// See https://github.com/dropwizard/metrics/blob/v3.1.0/metrics-core/src/main/java/com/codahale/metrics/ExponentiallyDecayingReservoir.java#L38
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const (
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	metricsReservoirSize = 1028
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	metricsAlphaFactor   = 0.015
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)
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func getOrRegisterHistogram(name string, r metrics.Registry) metrics.Histogram {
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	return r.GetOrRegister(name, func() metrics.Histogram {
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		return metrics.NewHistogram(metrics.NewExpDecaySample(metricsReservoirSize, metricsAlphaFactor))
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	}).(metrics.Histogram)
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}
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func getMetricNameForBroker(name string, broker *Broker) string {
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	// Use broker id like the Java client as it does not contain '.' or ':' characters that
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	// can be interpreted as special character by monitoring tool (e.g. Graphite)
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	return fmt.Sprintf(name+"-for-broker-%d", broker.ID())
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}
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func getMetricNameForTopic(name string, topic string) string {
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	// Convert dot to _ since reporters like Graphite typically use dot to represent hierarchy
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	// cf. KAFKA-1902 and KAFKA-2337
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	return fmt.Sprintf(name+"-for-topic-%s", strings.Replace(topic, ".", "_", -1))
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}
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func getOrRegisterTopicMeter(name string, topic string, r metrics.Registry) metrics.Meter {
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	return metrics.GetOrRegisterMeter(getMetricNameForTopic(name, topic), r)
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}
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func getOrRegisterTopicHistogram(name string, topic string, r metrics.Registry) metrics.Histogram {
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	return getOrRegisterHistogram(getMetricNameForTopic(name, topic), r)
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}
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